Scroll machines, such as scroll compressors using a fixed scroll and an orbiting scroll, are well known in the industry. Each of the scrolls of a scroll compressor has a spiral wrap extending axially from a base plate. The spiral wraps nest with one another to form pockets of varying volume. A fluid introduced into a low pressure area of the pockets is compressed by the cooperating movement of the spiral wraps, and discharged from a high pressure area proximate the center of the wraps. A motor drives a crankshaft which in turn drives the orbiting scroll along its circular orbital path via a slider block. A rotation prevention mechanism, such as an Oldham coupling, is used to prevent rotation of the orbiting scroll as it undergoes such orbital motion. Oldham couplings typically comprise a ring having a pair of upwardly projecting, diametrically opposed keys and a pair of downwardly projecting, diametrically opposed keys. In many applications the Oldham coupling is positioned between the orbiting scroll and a crankcase positioned within the scroll-type machine such that the pairs of keys mate with pairs of slots formed in the orbiting scroll and crankcase. In other applications, the Oldham coupling is positioned between the fixed and the orbiting scrolls, mating with corresponding pairs of slots formed in the fixed scroll and orbiting scroll.
U.S. Pat. No. 4,655,696 to Utter discloses an Oldham coupling positioned between a fixed scroll and an orbiting scroll, and which is stamped from sheet metal. The Oldham coupling of Utter has an annular ring with keys extending radially from the annular ring. The Oldham coupling of Utter is compact merely in an axial direction since the keys extend outwardly in a radial direction.
It is an object of the present invention to provide a scroll-type machine having a compact Oldham coupling which reduces or wholly overcomes some or all of the aforesaid difficulties inherent in prior known devices. Particular objects and advantages of the invention will be apparent to those skilled in the art, that is, those who are knowledgeable and experienced in this field of technology, in view of the following disclosure of the invention and detailed description of the preferred embodiments.